带有自定义验证的 Rspec 验证测试：未定义的方法和 nil 类错误

Question

我有一个简单的模型，付款属于贷款。我正在使用 rspec 和 shoulda-matcher 来测试验证。但是，我一直收到指向未结余额的错误——表明它是 nil 类的未定义方法。但是当我在 rails 控制台中使用模型时，这个验证是有效的。有谁知道为什么它没有通过测试？？？

谢谢。

class Payment < ActiveRecord::Base
  belongs_to :loan

  validates_presence_of :loan_id
  validate :proper_amount

  private

  def proper_amount
    errors.add(:amount, "proper") if amount > loan.outstanding_balance
  end
end

FactoryGirl.define do
  factory :payment do
    loan
    amount 100.0
    post_at Date.today
  end
end

FactoryGirl.define do
  factory :loan do
    funded_amount 5000.0
  end
end

RSpec.describe Payment do

  before (:all) do
    @loan = FactoryGirl.create(:loan)
    @payment = FactoryGirl.create(:payment, loan: @loan)
  end

  describe 'ActiveModel validations' do

    #basic validations on attributes
    it { should validate_presence_of(:loan_id) }
  end
end

Failure/Error: it { should validate_presence_of(:amount) }
NoMethodError:
  undefined method `outstanding_balance' for nil:NilClass

Answer 1

应该匹配器使用您尚未设置的主题。据我了解，RSpec 将初始化一个。

RSpec.describe Payment do

  let!(:loan){ FactoryGirl.create(:loan) }
  subject!(:payment){ FactoryGirl.create(:payment, loan: loan) }

  describe 'ActiveModel validations' do

    #basic validations on attributes
    it { should validate_presence_of(:loan_id) }
  end
end

现在，您需要在其他测试中使用贷款和付款，而不是使用 @loan 和 @payment。